<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>警告弹窗</title>
    <style>
        body {
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            margin: 0;
            background: linear-gradient(135deg, #0f172a, #1e293b);
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            overflow: hidden;
        }
        
        .container {
            text-align: center;
            padding: 50px;
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(10px);
            border-radius: 20px;
            border: 1px solid rgba(255, 255, 255, 0.2);
            box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
            z-index: 1;
        }
        
        h1 {
            color: #e2e8f0;
            margin-bottom: 30px;
            font-weight: 300;
            letter-spacing: 1px;
        }
        
        .alert-button {
            padding: 15px 40px;
            font-size: 18px;
            background: linear-gradient(45deg, #4a6ee0, #6a4bc2);
            color: white;
            border: none;
            border-radius: 50px;
            cursor: pointer;
            transition: all 0.3s ease;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
            letter-spacing: 1px;
            font-weight: 500;
        }
        
        .alert-button:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
            background: linear-gradient(45deg, #5a7ef0, #7a5bd2);
        }
        
        .alert-button:active {
            transform: translateY(1px);
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
        }
        
        .bg-bubbles {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: 0;
        }
        
        .bg-bubbles li {
            position: absolute;
            list-style: none;
            display: block;
            width: 40px;
            height: 40px;
            background-color: rgba(255, 255, 255, 0.15);
            bottom: -160px;
            animation: square 25s infinite;
            transition-timing-function: linear;
            border-radius: 5px;
        }
        
        .bg-bubbles li:nth-child(1) {
            left: 10%;
        }
        
        .bg-bubbles li:nth-child(2) {
            left: 20%;
            width: 90px;
            height: 90px;
            animation-delay: 2s;
            animation-duration: 17s;
        }
        
        .bg-bubbles li:nth-child(3) {
            left: 25%;
            animation-delay: 4s;
        }
        
        .bg-bubbles li:nth-child(4) {
            left: 40%;
            width: 60px;
            height: 60px;
            animation-duration: 22s;
            background-color: rgba(255, 255, 255, 0.25);
        }
        
        .bg-bubbles li:nth-child(5) {
            left: 70%;
        }
        
        .bg-bubbles li:nth-child(6) {
            left: 80%;
            width: 120px;
            height: 120px;
            animation-delay: 3s;
            background-color: rgba(255, 255, 255, 0.2);
        }
        
        .bg-bubbles li:nth-child(7) {
            left: 32%;
            width: 160px;
            height: 160px;
            animation-delay: 7s;
        }
        
        .bg-bubbles li:nth-child(8) {
            left: 55%;
            width: 20px;
            height: 20px;
            animation-delay: 15s;
            animation-duration: 40s;
        }
        
        .bg-bubbles li:nth-child(9) {
            left: 25%;
            width: 10px;
            height: 10px;
            animation-delay: 2s;
            animation-duration: 40s;
            background-color: rgba(255, 255, 255, 0.3);
        }
        
        .bg-bubbles li:nth-child(10) {
            left: 90%;
            width: 160px;
            height: 160px;
            animation-delay: 11s;
        }
        
        @keyframes square {
            0% {
                transform: translateY(0) rotate(0deg);
                opacity: 1;
            }
            100% {
                transform: translateY(-700px) rotate(600deg);
                opacity: 0;
            }
        }
    </style>
</head>
<body>
    <div class="container">
        <h1>点击警告弹窗按钮</h1>
        <button class="alert-button" onclick="showAlert()">点击</button>
    </div>
    
    <ul class="bg-bubbles">
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
    </ul>
    
    <script>
        function showAlert() {
            alert("这是一个警告弹窗！");
        }
    </script>
</body>
</html>